Electrochemically Stable Sodium Metal‐Tellurium/Carbon Nanorods Batteries

Abstract Electrochemical metal cells utilizing tellurium and sodium chemistry are being extensively explored for developing advanced high‐performance batteries. The daunting challenges, however, still remain with low rate capability/volumetric capacity, unclear redox reaction processes, and the notorious sodium dendrites. Here, a cell design that features a novel Te/carbon nanorods cathode and a tailored ether‐based electrolyte is reported. It is the first report of Na metal‐Te full batteries with performance comparable to those of reported Na‐S and Na‐Se batteries at low ratings. By using the semimetal Te instead of the insulating S or Se, the Na‐Te batteries actually outperform reported Na‐S and Na‐Se batteries at high ratings. Ab initio molecular dynamics simulations, UV–vis spectrum, ex situ X‐ray photoelectron spectroscopy, and scanning electron microscopy results clearly reveal a three‐step redox process and stability of the Na metal‐Te cells. These comprehensive results demonstrate the feasibility of practical Na metal‐Te batteries with high volumetric energy density and a viable cell fabrication cost.